Bookcase



FIG. 1 is perspective view of a bookcase showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a right side elevational view thereof, the left side elevational view being a mirror image thereof; and,

FIG. 5 is a rear elevational view thereof. 

The ornamental design for a bookcase, as shown and described. 